核心点：外层循环是item和index，内层循环是item2和index2

如果都是定义的同一个属性名
外层循环得写:prop="'block.'+index+'.numerical'"
同理内层循环就得写:prop="'objectSpecs.'+ index2 + '.numerical'"

校验函数方法 :rules="getRules(item2, item2.name)"

<div class="block" v-for="(item, index) in block" :key="index"><el-form ref="blockForm" :model="item" :rules="formBlockRule" :inline="true"><el-form-item>多个formItem...省略一下</el-form-item><div v-for="(item2,index2) in item.objectSpecs" :key="index2"><!--输入框--><el-form-item v-if="item2.input" :prop="'objectSpecs.' + index2 + '.numerical'" :label="item2.name" label-width="130px" :rules="getRules(item2, item2.name)"><el-input :placeholder="item2.placeholder" v-model="item2.numerical" :onkeyup="numberFormate(item2, 'numerical')" :disabled="readOnly"></el-input></el-form-item><el-form-item v-if="item2.input"><span>{{item2.units}}</span></el-form-item><!--选择框--><el-form-item v-if="!item2.input" :prop="'objectSpecs.' + index2 + '.numerical'" :label="item2.name" label-width="130px" :rules="getRules(item2, item2.name)"><el-select v-model="item2.numerical" placeholder="请选择" :disabled="readOnly"><el-option v-for="(key,value) in item2.numericalList" :key="value" :label="key" :value="value"></el-option></el-select></el-form-item></div></el-form>
</div>

getRules(item, name) {if(item.input){return [{ required: true, message: '请输入' + name, trigger: 'blur' },]}else{return [{ required: true, message: '请选择' + name, trigger: 'change' }];}
}